I would like my citations to be formatted according to the Chicago style, and at the same time numbered by order of appearance.

The sort&compress option does work as expected using unsrt bibliography style, with citations numbered by order of appearance. However, they get automatically sorted alphabetically as soon as I replace unsrt with chicago for the bibliography style:

\usepackage[numbers, sort&compress]{natbib}

... document...



Is it possible to get citations styled according to chicago but sorted according to unsrt (that is, by order of appearance)?

  • Is it the citations or the entries in the references section that you want to get styled a la chicago? Please advise.
    – Mico
    Feb 24, 2014 at 15:46
  • I want the entries in the references section to get styled a la chicago, but sorted in a numbered list according to their order of appearance. In the main text I do get the citations to appear as numbers into square brackets, as desired.
    – Didier
    Feb 24, 2014 at 16:09

1 Answer 1


Good news: You need to make only two small changes to the file chicago.bst to suppress the alphabetical sorting of the referenced items and, instead, to get them listed in the order they are first cited in the document.

  • Find the file chicago.bst in your TeX distribution and make a copy of this file. Name the copy, say, mychicago.bst. (Do not edit an original file of the TeX distribution directly.)

  • Open the file mychicago.bst in your favorite text editor; the editor you use to edit your TeX files will do fine.

  • Locate the two lines that start with SORT -- uppercase is important. In the copy of chicago.bst I found in my TeX distribution, the two lines in question are numbered 1565 and 1629.

  • Comment out these two lines, e.g., by inserting a % sign at the start of each of the two lines.

  • Save the file mychicago.bst, either to the directory that contains your main .tex file or to a directory that's searched by your TeX distribution. If you choose the latter method, be sure to update the TeX filename database in a way that's appropriate for your TeX distribution. If you don't understand the preceding sentence, you should probably go with the first option.

  • Start using the new bibliography style file by replacing the instruction \bibliographystyle{chicago} with \bibliographystyle{mychicago}.

  • As always after changing the bibliography style, be sure to run LaTeX, BibTeX, and LaTeX twice more on your document in order to fully propagate all changes.

The following example illustrates the effects of making use of the unsorted "chicago" style. Observe that while the three test entries are sorted alphabetically by authors' surnames in the bib file, they are sorted by the order of first citation in the formatted bibliopgraphy.

enter image description here

%\usepackage{filecontents} % update Apr 2024: not needed anymore

  author = "A. Author",
  title  = "Thoughts",
  journal= "Various Communications",
  year   = 3001,
  volume = 1,
  issue  = 1,
  pages  = "1-10",
  author = "B. Buthor",
  title  = "Further thoughts",
  journal= "Various Communications",
  year   = 3002,
  volume = 2,
  issue  = 1,
  pages  = "11-20",
  author = "C. Cuthor",
  title  = "Still more thoughts",
  journal= "Various Communications",
  year   = 3003,
  volume = 3,
  issue  = 1,
  pages  = "21-30",

\usepackage[numbers]{natbib}  % <-- nuneric-style citation call-outs
\bibliographystyle{mychicago} % <-- new bib style is in use

\cite{cc}, \cite{bb}, \cite{aa}

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